CVE-2021-3942Network attack vector

Unauthenticated code execution via LLMNR buffer overflow

Published Nov 22, 2022 · Updated Apr 25, 2025

Buffer overflow in HP Print and Digital Sending products allows remote attackers to execute code through LLMNR traffic. HP identifies LLMNR handling as the vulnerable locus but has not published the affected parser or the specific operation that crosses a buffer boundary. Unauthenticated network access to the link-local name-resolution service is sufficient; exploitation can execute code or interrupt the device.

CVSS severity8.4
High
EPSS probability1.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer overflow in HP Print and Digital Sending products allows remote attackers to execute code through LLMNR traffic. HP identifies LLMNR handling as the vulnerable locus but has not published the affected parser or the specific operation that crosses a buffer boundary. Unauthenticated network access to the link-local name-resolution service is sufficient; exploitation can execute code or interrupt the device.

The record

CVE
CVE-2021-3942
Published
Nov 22, 2022
Updated
Apr 25, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 25, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.4HP Inc.CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo